Moscow: A female Ukrainian pilot detained in Russia on murder charges that Kiev says are politically motivated restarted a hunger strike Monday that officials have warned could kill her, her lawyer told AFP.

Helicopter pilot Nadia Savchenko first went on hunger strike in December to protest against her arrest last year for alleged involvement in an attack that killed two Russian journalists on eastern Ukraine`s frontlines, where she had enlisted as a volunteer in one of the battalions fighting pro-Russian rebels.

Savchenko broke off the more-than-80-day hunger protest earlier this month after her health nearly collapsed but lawyer Mark Feigin told AFP that she was starting again as her basic demands had not been met.

"She insists that she is innocent," Feigin said.

Ukrainian medics paid a visit to the pilot over the weekend and strongly cautioned her not to go back on hunger strike, Feigin said.

"The doctors warned that she was not in any condition to begin the strike again, but she thinks differently," he said.

The 33-year-old Ukrainian military aviator lost more than 20 kilos (44 pounds) after being drip-fed on glucose and vitamins alone during the first round of the strike.

Savchenko has become a symbol of resistance in Ukraine, where she has been elected to parliament. She has been listed as a political prisoner by Russia`s most prominent rights group, Memorial, as well as by Amnesty International.

The pilot says she was abducted by pro-Russian rebels in eastern Ukraine and smuggled to Moscow, where she is now being detained.

Russia says she crossed the border of her own accord, pretending to be a refugee.